/Engine/Source/Runtime/GeometryCore/Public/Generators/SweepGenerator.h
Initializes the UV buffer with UV's that are set according to the diagram at the start ofGenerate(), with an extra element on each end in the case of closed curves, and distances weighted by distances in the corresponding curves. This function should get called after setting vertex positions so that the function can use them in case bUVScaleRelativeWorld is true.
void InitializeUvBuffer ( const [TArray](API\Runtime\Core\Containers\TArray)< int32 > & VertPositionOffsets, int32 & NumUvRowsOut, int32 & NumUvColumnsOut )